In the fabrication of semiconductor devices such as integrated circuits, memory cells, and the like, a series of manufacturing operations are performed to define features on substrates, such as semiconductor wafers. Some manufacturing operations, such as etching and deposition, include plasma processing operations that are performed in a plasma processing chamber in which a process gas is transformed into a plasma comprising reactive constituents that can perform work on the substrate when exposed thereto. During such plasma processing operations, the substrate is held on an electrostatic chuck in exposure to the plasma. The electrostatic chuck is defined to establish an electrostatic field that attracts the substrate to a supporting surface of the electrostatic chuck, thereby securing the substrate to the electrostatic chuck.
In some systems the electrostatic chuck needs to be heated to achieve desired plasma processing results on the substrate. Electric heaters are often used to provide heating of the electrostatic chuck. However, wiring and heating elements associated with such electric heaters can interfere with transmission of radiofrequency power through the electrostatic chuck to the plasma processing volume. Such interference with transmission of the radiofrequency power can cause non-uniformities in the radiofrequency power distribution across the plasma processing chamber, thereby causing non-uniformities in the plasma density generated within the plasma processing volume. It is within this context that the present invention arises.